Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 20 / 371

  • help
  • print

    Print search results

  • export
    A maximum of 250 titles can be exported. Please, refine your queryYou can also select and export up to 30 titles via your marked list.
  • alert
    We will mail you new results for this query: keywords==voedsel
Check title to add to marked list
Multi-objective decision-making for dietary assessment and advice
Lemmen - Gerdessen, J.C. van - \ 2017
Wageningen University. Promotor(en): J.G.A.J. Vorst; P. van 't Veer, co-promotor(en): G.D.H. Claassen. - Wageningen : Wageningen University - ISBN 9789463437073 - 136
questionnaires - food - fractionation - modeling - diet - food intake - decision making - diet counseling - vragenlijsten - voedsel - fractionering - modelleren - dieet - voedselopname - besluitvorming - dieetadvisering

Unhealthy diets contribute substantially to the worldwide burden of non-communicable diseases, such as cardiovascular diseases, cancers, and diabetes. Globally, non-communicable diseases are the leading cause of death, and numbers are still rising, which makes healthy diets a global priority. In Nutrition Research, two fields are particularly relevant for formulating healthier diets: dietary assessment, which assesses food and nutrient intake in order to investigate the relation between diet and disease, and dietary advice, which translates food and nutrient recommendations into realistic food choices. Both fields face complex decision problems: which foods to include in dietary assessment or advice in order to pursue the multiple objectives of the researcher or fulfil the requirements of the consumer. This thesis connects the disciplines of Nutrition Research and Operations Research in order to contribute to formulating healthier diets.

In the context of dietary assessment, the thesis proposes a MILP model for the selection of food items for food frequency questionnaires (a crucial tool in dietary assessment) that speeds up the selection process and increases standardisation, transparency, and reproducibility. An extension of this model gives rise to a 0-1 fractional programming problem with more than 200 fractional terms, of which in every feasible solution only a subset is actually defined. The thesis shows how this problem can be reformulated in order to eliminate the undefined fractional terms. The resulting MILP model can solved with standard software.

In the context of dietary advice, the thesis proposes a diet model in which food and nutrient requirements are formulated via fuzzy sets. With this model, the impact of various achievement functions is demonstrated. The preference structures modelled via these achievement functions represent various ways in which multiple nutritional characteristics of a diet can be aggregated into an overall indicator for diet quality. Furthermore, for Operations Research the thesis provides new insights into a novel preference structure from literature, that combines equity and utilitarianism in a single model.

Finally, the thesis presents conclusions of the research and a general discussion, which discusses, amongst others, the main modelling choices encountered when using MODM methods for optimising diet quality.

Summarising, this thesis explores the use of MODM approaches to improve decision-making for dietary assessment and advice. It provides opportunities for better decision-making in research on dietary assessment and advice, and it contributes to model building and solving in Operations Research. Considering the added value for Nutrition Research and the new models and solutions generated, we conclude that the combination of both fields has resulted in synergy between Nutrition Research and Operations Research.

The effect of date marking terminology of products with a long shelf life on food discarding behaviour of consumers
Holthuysen, Nancy ; Kremer, Stefanie ; Bos-Brouwers, Hilke - \ 2017
Wageningen : Wageningen Food & Biobased Research (Wageningen Food & Biobased Research report 1709) - ISBN 9789463432290 - 26
keeping quality - food - food wastage - nutrition labeling - terminology - consumer behaviour - houdbaarheid (kwaliteit) - voedsel - voedselverspilling - etiketteren van voedingsmiddelen - terminologie - consumentengedrag
Food online : PhD thesis on food legal and civil law requirements for digital contracts regarding food purchases by consumers in the Netherlands
Veer, Lomme C. van der - \ 2017
Wageningen University. Promotor(en): B.M.J. Meulen. - Wageningen : Wageningen University - ISBN 9789463437127 - 125
food - food consumption - food costs - food marketing - food merchandising - food prices - food legislation - consumers - product liability - regulations - law - internet - netherlands - food purchasing - voedsel - voedselconsumptie - kosten voor voedsel - marketing van voedingsmiddelen - reclamecampagne van voedsel - voedselprijzen - voedingsmiddelenwetgeving - consumenten - productaansprakelijkheid - regelingen - recht - internet - nederland - voedselinkoop

In this thesis the research focuses on the legal rules and regulations in the Netherlands that apply in the context of food purchases by consumers that are concluded online. Sale of food via the Internet takes place in the area of Civil Code requirements on distance selling and public law requirements on food labelling. In four research Chapters (chapters 2-5) the relevant topics are addressed.

In Chapter 1 the legal context to the research is presented leading up to the formulation of the central problem statement and the research questions. The Chapter also provides the theoretical framework and the in this research applied methodology.

Chapter 2 ‘'Real Food from Virtual Shops: the situation before 2014’ reports on research performed before the entry into force of the national implementation of the Consumer Rights Directive and of the Food Information Regulation. This chapter provides the historical baseline to this research. The research in this chapter shows that the instruments handed to the consumers to compensate their weakened position as online buyers, cannot function as intended in case the merchandise is food. It is argued that consumers derive more bite from general provisions of contract law than from the provisions specifically addressing distance contracts.

In Chapter 3, ‘Food Online, Radical Changes to the Digital Shop Window after 2014’ the argument is continued by addressing in detail the implementation of the Consumer Rights Directive in the Netherlands and the entry into force of the Food Information Regulation. The differences become visible between civil law and public food legislation in the manner in which they envisage to protect the consumer. Civil law turns out to be rather scarce in requiring information provision to consumers. In his attempt to ensure that consumers are only bound to purchase contracts they actually want, the European legislator has chosen a far more draconic instrument. The consumer has been given the right to withdraw from the contract altogether after the etailer has already fulfilled his side of the agreement. The legislature has preferred this instrument over elaborate information requirements regarding the product to be purchased. The available data do not show that the legislature balanced these two instruments.

Whatever these reasons have been, they seem to have been less compelling in the case of food products. The vast majority of foods is exempted from the consumers' right to withdraw. This leaves a considerable gap in the civil law protection of consumers of food online. This gap has recently been filled by the Food Information Regulation. This regulation does put in place a considerable obligation to supply the consumer online with information prior to the purchase decision. The etailer has to provide online all the information which the producer is required to provide on the food label. In one small provision the entire and complex burden the Food Information Regulation places on the food industry, is placed with the etailer as well.

In Chapter 4 ‘Product Liability for Online Food Suppliers’ the increased risks for the etailer of foods to become product liable is addressed. Due to the wide scope of the definition of ‘producer’ in product liability law, the risk for the etailer to be considered the liable producer is rather high. Due to the Consumer Rights Directive and its implementation in national law, of all the players in the chain the etailer is easiest to identify for the consumer. Etailers have to push their claims further up the hill without any recourse to facilities regarding burden of proof or liability. Both the Consumer Rights Directive and the Food Information Regulation have been designed to reinforce the consumers’ position with a view to ensuring that consumers will no longer be the weakest link in the value chain.

In Chapter 5 'The Lucky Bag for Meals' the emerging market for food-boxes is discussed. Food-boxes embody the dream of every etailer. Not the consumers decide what they buy, but the retailers decide what they supply. Business economic advantages of this model in terms of stock management, logistics and marketing are obviously enormous. Apparently an important marketing proposition in this modern day ‘lucky bag’ is the surprise. It appears that consumers want to be surprised. Despite all requirements regarding transparency and information provision imposed by legislators upon the etailer with a view to protecting consumers, a part of the market seems to prefer to be kept uninformed. The chapter shows that a relevant group of consumers is actually willing to pay a price premium to businesses for infringing upon their legal obligations and for being kept out of their rights.

In Chapter 6 the findings of the research are presented. Besides the answers to the research questions a new series of questions emerge. These openings to further exploration show how the legal field of food online in legal development and legal scholarship is just as young as the technology that sparked its emergence.

Food reward from a behavioural and (neuro)physiological perspective
Bruijn, Suzanne E.M. - \ 2017
Wageningen University. Promotor(en): C. de Graaf; R.F. Witkamp, co-promotor(en): G. Jager. - Wageningen : Wageningen University - ISBN 9789463436748 - 154
food - physiological functions - feeding behaviour - food preferences - perception - hormones - responses - neurohormonal control - stomach bypass - gastric bypass - satiety - voedsel - fysiologische functies - voedingsgedrag - voedselvoorkeuren - perceptie - hormonen - reacties - neurohormonale controle - maag bypass - buik bypass - verzadigdheid

Food reward is an important driver of food intake and triggers consumption of foods for pleasure, so-called hedonic eating, even in the absence of any energy deficits. Hedonic eating can trigger overeating and may therefore lead to obesity. Given the rise in obesity rates and the health risks associated with being obese, hedonic eating and food reward are important phenomena to study. This thesis aimed to add on to the existing knowledge on food reward. The phenomenon was approached from a behavioural, sensory and (neuro)physiological perspective in healthy, lean and in obese gastric bypass populations.

For the behavioural perspective, the main outcome measure used in this thesis was food preferences. To be able to study food preferences for four macronutrient and two taste categories, a new food preference task was developed. In chapter 2, the development and validation of the Macronutrient and Taste Preference Ranking Task (MTPRT) were described. The MTPRT uses a ranking method to determine preferences for four macronutrient (high-carbohydrate, high-fat, high-protein, low-energy) and two taste (sweet and savoury) categories.

For the sensory and physiological perspective, focus was put on the endocannabinoid system (ECS): a neuromodulatory system that plays a role in food reward. To gain more insight into this role, the effect of ECS modulation with pharmacological challenges on sensory perception of sweet taste and on food preferences were studied, as well as endocannabinoid responses to food intake. In chapter 3 it was shown that inhaling Cannabis with low doses of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) does not alter sweet taste intensity perception and liking in humans, nor does it affect food preferences. Vice versa, in chapter 4 it was found that liking of a food taste does not affect endocannabinoid responses to food intake, after controlling for expectations. When palatability of the food is unknown until the first bite, response of endocannabinoids, ghrelin and pancreatic polypeptide did not differ between a palatable and a neutral food across anticipatory, consummatory and post-ingestive phases of food intake. Endocannabinoid and ghrelin plasma concentrations decreased after food intake, which suggests an orexigenic function for endocannabinoids.

In chapters 5, 6 and 7, studies with patients who underwent Roux-en-Y gastric bypass surgery were described. These studies were intended to gain more insight into alterations in food reward in relation to (morbid) obesity and in response to surgical treatment by RYGB surgery.

First, in chapter 5 food preferences were assessed before, and at two months and one year after RYGB. It was shown that patients have decreased preference for high-carbohydrate and high-fat foods, and increased preference for low-energy foods after compared with before surgery. In addition, liking ratings for the high-carbohydrate and high-fat foods were decreased after RYGB surgery, whereas liking of low-energy products changed minimally. Potential mechanisms behind these alterations in food preferences include changes in neural processing of food cues and changes in appetite-related gut hormones.

In chapter 6, it was shown that alterations in food preferences after RYGB surgery are indeed related to changes in neural activation in response to food cues. With regards to the appetite-related hormones it was shown that plasma concentrations of the endocannabinoid anandamide were increased after compared with before surgery. Plasma concentrations of other endocannabinoids and ghrelin did not change. Moreover, changes in endocannabinoid or ghrelin concentrations did not correlate with changes in food preferences or neural response to food cues. Together, these results suggest that changes in neural processing of food cues contribute to changes in food preferences towards low-energy foods, and provide a first indication that the endocannabinoid system does not seem to play a role in this process.

To gain more insight into behavioural responses to food cues, a response-inhibition paradigm was used in chapter 7, in which response-inhibition to high-energy and low-energy food cues was assessed during brain imaging. The behavioural data did not show differences in performance when comparing before and two months after RYGB surgery. The brain imaging data showed that activation in reward-related brain areas was decreased in response to both high- and low-energy food pictures after RYGB surgery. Also, prefrontal brain areas were more activated in response to the high-energy pictures, which suggests improved response inhibition.

In conclusion, the findings in this thesis show that modulating the ECS with low doses of THC and CBD does not influence sweet taste perception and liking and food preferences, and vice versa, food taste liking in the absence of expectations does not affect endocannabinoid responses to food intake. With regards to RYGB surgery it was uncovered that changes in food preferences after RYGB surgery are related to altered brain reward processing, but no relation with changes in endocannabinoid tone was found. The success of RYGB surgery and the changes in food choice might in part be caused by an improved inhibitory response to high-energy foods.

What if the trucks stop coming? : exploring the framing of local food by cooperative food retailers in New Mexico
Constance, Cheron Z. - \ 2017
Wageningen University. Promotor(en): J.S.C. Wiskerke, co-promotor(en): L.G. Horlings; L. Shaw. - Wageningen : Wageningen University - ISBN 9789463431941 - 261
food - agricultural products - cooperatives - cooperative farm enterprises - food products - new mexico - voedsel - landbouwproducten - coöperaties - coöperatieve landbouwbedrijven - voedselproducten - new mexico

Proponents of local food cite a variety of economic and environmental advantages of short food supply chains. Consumer interest in local food has also offered a point of differentiation for many players in the food industry, including restaurants and grocery stores. Engaging with local food has significant challenges, however, and many production and distribution systems engender and support more diffuse food provisioning, not less. Though food can travel thousands of miles from its point of origin to consumption, many cooperative (co-op) grocery stores have long sold locally-produced food and have deep ties to their supplier communities. This thesis offers case studies of two co-ops in the natural and organic food sector and examines how they think about and work with local food. The theories of embeddedness (after Polanyi) and diverse economies (from Gibson-Graham) undergird the analyses of these co-ops’ involvement with local food and how the cooperative business model relates to it.

Sugar beet leaves for functional ingredients
Tamayo Tenorio, Angelica - \ 2017
Wageningen University. Promotor(en): R.M. Boom, co-promotor(en): A.J. van der Goot. - Wageningen : Wageningen University - ISBN 9789463431378 - 188
sugarbeet - leaves - thylakoids - cellulosic fibres - food - surface proteins - food crops - protein extraction - suikerbieten - bladeren - thylakoïden - cellulosevezels - voedsel - oppervlakte-eiwitten - voedselgewassen - eiwitextractie

Plant leaves are recognised as a potential source for food applications based on their nutritional profile and interesting technological properties of leaf components, and based on the large availability of plant leaves in agricultural waste streams. Besides proteins, leaves have a rich nutritional profile (e.g. dietary fibres, minerals and secondary metabolites) and consist of complex biological structures (e.g. chloroplastic membranes) that can be explored as novel fractions that ultimately broaden the use of leaves. The overall aim of this thesis is to explore green leaves as a food source, with emphasis on neglected leaf fractions. This thesis describes a processing approach that aims at separating/generating enriched- functional fractions rather than pure components, and highlights the implications for value creation out of green leaves. The extraction of leaf membrane proteins is investigated using a proteomics extraction method, while the properties of other valuable leaf components (complexes and fibres) are analysed for techno-functional applications. Furthermore, the feasibility of leaves as a food source is studied at an industrial scale, considering large scale processing and options for leaf stabilisation.

The extraction of proteins from sugar beet leaves is evaluated in Chapter 2 by using a traditional heat coagulation method. The heat treatment is thought to precipitate the insoluble proteins together with fibres, chlorophyll and other components, resulting in a green curd. Therefore, the distribution of soluble and insoluble proteins was followed along the extraction process to discern the effect of the heating step on protein fractionation. This study showed that both soluble and insoluble protein distribute almost evenly over the leaf fractions juice, pulp, supernatant and final pellet. The even distribution of the proteins was attributed to the anatomy of leaves and their biological function, which is predominantly the enzymatic activity related to photosynthesis instead of protein storage, which occurs in other plant tissues. This chapter further concludes that striving for high purity severely compromises the yield, and consequently results in inefficient use of the leave proteins.

Chapter 3 describes the application of proteomic analytical extraction protocols to analyse the fractionation behaviour of leaf proteins. This analysis lead to the translation into food- grade processes based on four fundamental extraction steps: (1) tissue disruption, (2) enzymatic inhibition, (3) removal of interfering compounds, and (4) protein fractionation and purification. Part of these extraction steps can be translated into food-grade alternatives, while the processing conditions determine the potential properties for food of the final products. Nevertheless, it was concluded that harsh and/or non-food grade conditions were required to isolate the leaf membrane proteins with high purity. Those results were explained by the fact that membrane proteins are heterogeneous w.r.t. charge, hydrophobicity, post- translational modification and complexation, leading to non-selective behaviour when compared with a single pool of proteins.

Given the large challenges in isolating membrane proteins from leaves, we studied another approach in which green leaves are considered as a source of naturally structured elements that have relevant techno-functional properties for food products, like the chloroplastic membranes (i.e. thylakoid membranes) and cellulose-rich fibres. Chapter 4 describes the properties of thylakoid membranes and their emulsifying mechanism. These membranes showed surface active properties and their adsorption kinetics were typical for large molecules or soft particles. The thylakoid fragments can effectively stabilise emulsion droplets, even though aggregation was observed already during emulsion preparation and increased with increased thylakoid concentration. Both composition and structure make thylakoid membranes suitable as a biobased material for food and pharma applications.

To continue exploring valuable fractions from leaves, Chapter 5 reports on the interfacial behaviour of cellulose-rich particles obtained from leaf pulp. Cellulosic particles were produced from the pulp obtained after leaf pressing. The particles spontaneous adsorption onto the oil-water interface and interfacial behaviour similar to that of solid particles. Addition of cellulosic particles to oil-in-water emulsions resulted in stable emulsions above a particle concentration of 0.1 w/v%, although phase separation was observed. The particle fines (0.04 – 1.0 µm) stabilised the droplet interface, while large particles formed a network in the continuous phase and rendered a top (green) phase in the emulsions. Finding applications for leaf side streams, like leaf pulp, broadens the options for total leaf processing and contributes to resource use optimisation.

A sustainability assessment of leaf processing is discussed in Chapter 6, considering the challenges that may appear at industrial scale. The seasonal availability of sugar beet plants implies the need of processing large amounts of biomass within a short time due to their high moisture content (85 - 90%) and their sensitivity to spoilage. Processing options were evaluated on their resource use efficiency in terms of energy requirement and exergy indicators. A decentralised process constitutes a good option compared to freezing, since solid side streams can be directly returned the land, leaving nutrients to the soil, and reducing transportation loads. With a decentralised process, freezing of the leaves becomes unnecessary; the leaf juice is transported while chilled, resembling the transportation of fresh milk that is also chill-transported from the farm to a central factory.

Chapter 7 concludes this thesis with a general discussion of the main findings. An integrated process for leaf valorisation is described, which combines the production of functional fractions with the production of bulk products such as protein-rich and fibre-rich fractions. A compilation of data on protein yield and protein purity of fractions obtained from protein crops (e.g. soy, lupine beans, pulses) and from photosynthetic active tissues (e.g., leaves, algae, duckweed) is included. Protein crops reach 50 - 60% protein yield with a protein purity of ~ 90%, whereas leaves and other photosynthetic active tissues reach similar protein purity (60 – 80 w/w% protein) but at much lower yields (10%). We hypothesize that the low yields are due to the small length scale in which protein is structured inside the leaves and the lack of protein storage anatomy in these tissues. Therefore, we conclude that leaf valorisation requires non-conventional approaches that go beyond higher extraction yields but that consider a complete use of the biomass.

How to achieve resource use efficiency in integrated food and biobased value chains?
Annevelink, E. ; Gogh, J.B. van; Bartels, P.V. ; Broeze, J. ; Dam, J.E.G. van; Groot, J.J. ; Koenderink, N.J.J.P. ; Oever, M.J.A. van den; Snels, J.C.M.A. ; Top, J.L. ; Willems, D.J.M. - \ 2017
Wageningen : Wageningen Food & Biobased Research (Wageningen Food & Biobased Research report 1720) - ISBN 9789463431163 - 23
resources - biobased economy - food chains - food biotechnology - biomass - change - sustainability - value chain analysis - efficiency - use efficiency - food - resource management - integrated systems - hulpbronnen - voedselketens - voedselbiotechnologie - biomassa - verandering - duurzaamheid (sustainability) - waardeketenanalyse - efficiëntie - gebruiksefficiëntie - voedsel - hulpbronnenbeheer - geïntegreerde systemen
Effect van houdbaarheidsdata van lang houdbare producten op weggooigedrag van consumenten
Holthuysen, N.T.E. ; Kremer, S. ; Bos-Brouwers, H.E.J. - \ 2016
Wageningen : Wageningen Food & Biobased Research (Wageningen Food & Biobased Research rapport 1709) - ISBN 9789463430852 - 22 p.
houdbaarheid (kwaliteit) - voedsel - voedselverspilling - etiketteren van voedingsmiddelen - terminologie - consumentengedrag - keeping quality - food - food wastage - nutrition labeling - terminology - consumer behaviour
The transmission and management of price volatility in food supply chains
Assefa, Tsion Taye - \ 2016
Wageningen University. Promotor(en): Alfons Oude Lansink, co-promotor(en): Miranda Meuwissen. - Wageningen : Wageningen University - ISBN 9789462579835 - 132
food prices - agricultural prices - volatility - cap - food - supply chain management - price controls - voedselprijzen - landbouwprijzen - vluchtigheid - gemeenschappelijk landbouwbeleid - voedsel - ketenmanagement - prijsbewaking

The 2006-2011 period has been marked by increased volatility in food an agricultural commodity prices at a global level. In the EU, the continuous liberalization of agricultural markets under the Common Agricultural Policy has led to the exposure of EU agricultural to increasing market price volatility. This thesis has investigated the transmission and management of price volatility in EU food supply chains. The transmission of price volatility in various food supply chains is first investigated through a literature review followed by an empirical analysis of price volatility transmission in the case of the German fresh pork supply chain. The effect of market power was also taken into account in the latter empirical analysis. Next, the management of price volatility was investigated through interviews conducted with actors of selected EU food supply chains. This was followed by the analysis of the effectiveness of selected price volatility management strategies. Lastly, in light of the policy support for agricultural insurance within the Common agricultural policy, premium rates of an agricultural revenue insurance contract were calculated for the Dutch ware potato sector.

One of the gaps identified in the reviewed literature is the lack of attention given to the effects of contextual factors on price volatility transmissions in food supply chains. Contextual factors include market power in the chain and pricing strategies (e.g. contracts) by chain actors. Results of the price volatility transmission analysis conducted in this thesis in the case of the German pork chain show that retail market power limited both the transmission of price levels and price volatility. This thesis shows that price volatility is perceived as risky by all actors in the food supply chain. Deviations of prices by more than 10 to 15 % from expected levels were perceived as price volatility by a majority of the chain actors. Results further show that price volatility management strategies in EU food chains are diverse and well beyond traditional instruments such as futures and forward contracts. Contrary to expectations, price fixing contracts were not found to be desirable by interviewed chain actors. This thesis also found that the effectiveness of contracts in reducing price volatility depended on how the contract price was set.

Results of this thesis further show that premium rates of a revenue insurance contract for the Dutch ware potato sector across categories of farms. The average premium rates calculated were 32.1%, 22.2%, 33.1% and 24.0% on guaranteed revenue per hectare for the high expected yield, low expected yield, high yield variance to expected yield ratio and low yield variance to expected yield ratio categories of farm, respectively. The difference in premium rates across categories of farms implies that charging the same average premium rate to all Dutch ware potato farms can lead to adverse selection.

Networks, flows and actors : promoting sustainability in globalising food provision
Oosterveer, Peter J.M. - \ 2016
Wageningen : Wageningen University - ISBN 9789462579750 - 24
networks - sustainability - globalization - food - health - social sciences - food chains - governance - netwerken - duurzaamheid (sustainability) - globalisering - voedsel - gezondheid - sociale wetenschappen - voedselketens
Cater with Care : impact of protein-enriched foods and drinks for elderly people
Beelen, J. - \ 2016
Wageningen University. Promotor(en): Lisette de Groot; Frans Kok, co-promotor(en): Nicole de Roos. - Wageningen : Wageningen University - ISBN 9789462578814 - 142
undernutrition - hospital catering - hospitals - protein - elderly - protein intake - food - beverages - diet studies - dietetics - dietitians - randomized controlled trials - ondervoeding - ziekenhuiscatering - ziekenhuizen - eiwit - ouderen - eiwitinname - voedsel - dranken - dieetstudies - diëtetiek - diëtisten - gestuurd experiment met verloting

Protein undernutrition is a major health concern for older adults, especially for those who are ill. There is growing consensus for a protein intake target of 1.2 - 1.5 gram per kg bodyweight per day (g/kg/d) for these older adults. However, this target is not reached by the majority of older adults. Therefore, more effective and novel strategies to increase protein intake are warranted, including the use of protein-enriched foods and drinks. This thesis evaluated the impact of the developed protein-enriched foods and drinks on protein intake and physical performance among older adults. The studies in this thesis were done as part of the Cater with Care® project; a collaboration between the university, care organizations, and partners from the food industry. The industrial partners developed the products, focusing each on different product categories: Carezzo Nutrition developed bread, pastry, and fresh juices and soups; The Kraft Heinz Company focused on long shelf-life and convenience foods; and the Veal Promotion Foundation produced veal meat.

To fit the products to the needs of the target group, interviews with undernourished older adults (at home or hospitalized) and with dietitians were conducted (chapter 2). These interviews showed that undernutrition awareness is low among older adults. To treat undernutrition by changing their eating habits, older adults need to be aware of their health problem, they need to be willing to change, and they need to be able to understand and implement the dietitian’s advices. This process takes time while undernutrition should be treated immediately. For immediate treatment, enriched products could be used, without first creating awareness. According to the interviewees, enriched products should fit within older adults’ eating habits, and have small portion sizes.

To gain insights in food choices of hospitalized older adults (65 years and older) an observational study was conducted. In this study, energy and protein intakes of 80 hospitalized older patients at low and high risk of undernutrition were assessed (chapter 3). Patients who received an energy- and protein-rich menu, because of their risk of undernutrition, were better able to reach the protein and energy targets than patients with a low risk of undernutrition receiving a standard menu. Based on these results we proposed that all hospitalized older adults – both at low and high risk of undernutrition – should receive an energy- and protein-rich menu.

Subsequently, a pilot study was done in a care home and a rehabilitation center with the aim to explore the potential of the developed protein-enriched products to increase protein intake (chapter 4). Participants did not compensate their consumption of regular protein-rich foods (e.g. dairy, cheese) upon the introduction of protein-enriched foods and drinks. The 22 institutionalized elderly (mean age 83 years) consumed 12 gram protein per day more than they did before the intervention. Consequently, more people met the protein target of 1.2 g/kg/d than before the intervention. We concluded that protein-enriched products enabled institutionalized elderly to reach protein intake targets. Furthermore, we gained valuable feedback to improve the assortment of protein-enriched products for the effectiveness study.

In the final study, effects of the protein-enriched products on protein intake and physical performance were studied in a randomized controlled trial during hospitalization and subsequent recovery at home. During the hospital period in which 147 older patients participated, patients that received protein-enriched products increased their protein intake compared to the control group that already received a protein-rich hospital menu (chapter 5). As a result, 79% of the intervention group reached a protein intake of 1.2 g/kg/d, compared to 48% of the control group. Finally, effects of the protein-enriched products were tested at home, for a longer period (chapter 6). Half of the hospital phase participants (n = 75) continued the intervention at home for 12 weeks. The protein-enriched products were successfully implemented in the daily menu of the older adults: the intervention group had a higher average protein intake (1.5 ± 0.6 g/kg/d) than the control group (1.0 ± 0.4 g/kg/d) during the 12-week intervention period. Seventy-two percent of the intervention group reached a protein intake of 1.2 g/kg/d during the 12-week intervention, compared to 31% of the control group. Protein intake of the intervention group was mainly increased by the following protein-enriched products: bread, dairy drinks, dairy desserts, soups, and fruit juices. However, despite the successful improvement of protein intake, we found no added value on physical performance in the first 6 months after hospitalization.

It was concluded that with the protein-enriched familiar foods and drinks, we have a feasible, acceptable, and appetizing long-term strategy to increase protein intake of older adults in various settings. We envisage a beneficial role of these protein-enriched products in combination with physical activity in older adults with lower protein intakes.

Disentangling the domestic contract : understanding the everyday-life construction of acceptability -or non-acceptability- of keeping and killing animals for food
Nijland, Hanneke J. - \ 2016
Wageningen University. Promotor(en): Cees van Woerkum; Noelle Aarts. - Wageningen : Wageningen University - ISBN 9789462578296 - 325
meat - vegetarians - vegetarianism - vegetarian diets - killing of animals - meat animals - meat production - households - environmental impact - sustainability - animal welfare - animal production - animal ethics - food - dairy cattle - beef cattle - pigs - poultry - broilers - hens - vlees - vegetariërs - vegetarisme - vegetarische diëten - doden van dieren - slachtdieren - vleesproductie - huishoudens - milieueffect - duurzaamheid (sustainability) - dierenwelzijn - dierlijke productie - dierethiek - voedsel - melkvee - vleesvee - varkens - pluimvee - vleeskuikens - hennen

When we were children learning the names of animals, farm utensils and food products from picture books, talking about farming animals and related food products appeared simple. However, the intricate realities of modern-day farming practices differ momentously from this primary reference - the picture books. The topic brings about polarized responses, both rationally and emotionally, reflecting very diverse outlooks on the world. This dissertation reports on a research, set in the Netherlands and Turkey, that was designed to improve our understanding of the everyday-life construction of the acceptability -or non-acceptability- ofkeeping and killing animals for food, or in other words: to disentangle the domestic contract.

Trajectories of agricultural change in southern Mali
Falconnier, G.N. - \ 2016
Wageningen University. Promotor(en): Ken Giller, co-promotor(en): Katrien Descheemaeker; T.A. van Mourik. - Wageningen : Wageningen University - ISBN 9789462577596 - 209
agriculture - agricultural development - farms - classification - self sufficiency - food - income - intensification - farming systems - intensive production - mali - landbouw - landbouwontwikkeling - landbouwbedrijven - classificatie - zelfvoorziening - voedsel - inkomen - intensivering - bedrijfssystemen - intensieve productie - mali

Key words: longitudinal study, farm typology, food self-sufficiency, income, legumes, ex-ante analysis, participatory research, scenario.

Smallholder agriculture in sub-Saharan Africa provides basis of rural livelihoods and food security, yet farmers have to cope with land constraints, variable rainfall and unstable institutional support. This study integrates a diversity of approaches (household typology and understanding of farm trajectories, on-farm trials, participatory ex-ante trade-off analysis) to design innovative farming systems to confront these challenges. We explored farm trajectories during two decades (1994 to 2010) in the Koutiala district in southern Mali, an area experiencing the land constraints that exert pressure in many other parts of sub-Saharan Africa. We classified farms into four types differing in land and labour productivity and food self-sufficiency status. During the past two decades, 17% of the farms stepped up to a farm type with greater productivity, while 70% of the farms remained in the same type, and only 13% of the farms experienced deteriorating farming conditions. Crop yields did not change significantly over time for any farm type and labour productivity decreased. Together with 132 farmers in the Koutiala district, we tested a range of options for sustainable intensification, including intensification of cereal (maize and sorghum) and legume (groundnut, soyabean and cowpea) sole crops and cereal-legume intercropping over three years and cropping seasons (2012-2014) through on-farm trials. Experiments were located across three soil types that farmers identified – namely black, sandy and gravelly soils. Enhanced agronomic performance was achieved when targeting legumes to a given soil type and/or place in the rotation: the biomass production of the cowpea fodder variety was doubled on black soils compared with gravelly soils and the additive maize/cowpea intercropping option after cotton or maize resulted in no maize grain penalty, and 1.38 t ha−1 more cowpea fodder production compared with sole maize. Farm systems were re-designed together with the farmers involved in the trials. A cyclical learning model combining the on-farm testing and participatory ex-ante analysis was used during four years (2012-2015). In the first cycle of 2012-2014, farmers were disappointed by the results of the ex-ante trade-off analysis, i.e marginal improvement in gross margin when replacing sorghum with soybean and food self-sufficiency trade-offs when intercropping maize with cowpea. In a second cycle in 2014-2015 the farm systems were re-designed using the niche-specific (soil type/previous crop combinations) information on yield and gross margin, which solved the concerns voiced by farmers during the first cycle. Farmers highlighted the saliency of the niches and the re-designed farm systems that increased farm gross margin by 9 to 29% (depending on farm type and options considered) without compromising food self-sufficiency. The involvement of farmers in the co-learning cycles allowed establishment of legitimate, credible and salient farm reconfiguration guidelines that could be scaled-out to other communities within the “old cotton basin”. Five medium-term contrasting socio-economic scenarios were built towards the year 2027, including hypothetical trends in policy interventions and change towards agricultural intensification. A simulation framework was built to account for household demographic dynamics and crop/livestock production variability. In the current situation, 45% of the 99 households of the study village were food self-sufficient and above the 1.25 US$ day-1 poverty line. Without change in farmer practices and additional policy intervention, only 16% of the farms would be both food self-sufficient and above the poverty line in 2027. In the case of diversification with legumes combined with intensification of livestock production and support to the milk sector, 27% of farms would be food self-sufficient and above the poverty line. Additional broader policy interventions to favour out-migration would be needed to lift 69% of the farms out of poverty. Other additional subsidies to favour yield gap narrowing of the main crops would lift 92% of the farm population out of poverty. Whilst sustainable intensification of farming clearly has a key role to play in ensuring food self-sufficiency, and is of great interest to local farmers, in the face of increasing population pressure other approaches are required to address rural poverty. These require strategic and multi-sectoral approaches that address employment within and beyond agriculture, in both rural and urban areas.

Understanding place brands as collective and territorial development processes
Donner, M.I.M. - \ 2016
Wageningen University. Promotor(en): F. Fort; Cees Leeuwis, co-promotor(en): Sietze Vellema. - Wageningen : Wageningen University - ISBN 9789462577992 - 178
rural sociology - food consumption - food - branding - marketing - morocco - france - regional development - rural development - tourism - international tourism - rurale sociologie - voedselconsumptie - voedsel - brandmerken - marketing - marokko - frankrijk - regionale ontwikkeling - plattelandsontwikkeling - toerisme - internationaal toerisme

Place branding strategies linking marketing to places have received increasing attention in practice and theory in the past two decades. It is generally assumed that place branding contributes to the economic, social, political and cultural development of cities, regions and countries. But there exists neither a commonly accepted definition nor a sound theoretical framework for place branding research. Studies have until now mainly focused on nations and cities, while the regional scale has rather been neglected, even more in the context of Mediterranean countries. In addition, little is yet known about the conditions, processes, and outcomes of place branding.

The objective of this thesis is to contribute to the clarification of the place branding concept and to a broader understanding of this rich and complex phenomenon. The focus is on the underlying conditions, processes and dynamics of place branding in regions that contributes to territorial development. Place branding is related to local food products and tourism for sustainable territorial development in Mediterranean rural regions (in France and Morocco).

The introduction chapter outlines the societal and theoretical context of place branding regarding this thesis. Place brands have emerged as attempts to respond to intertwined and multifaceted economic, political and socio-cultural challenges: to the externalities of globalisation, to local development challenges due to regionalisation and decentralisation processes, and to socio-economic tensions in the Mediterranean basin and its food domain. Accordingly, three established literature streams are mobilized: the marketing and branding of places, regional studies and sociology. It is supposed that insights from the three disciplines are needed to understand the conditions, processes and development outcomes of regional branding. This leads to three units of analysis: the first deals with place branding in a narrow sense, understanding it as marketing strategy for the development of places and their local assets based on a distinctive territorial identity; the second considers territorial development policies and public-private interactions; and the third analyses place-based, collective and embedded processes among various actors in rural areas.

Chapter 2 comprises a case study of the Sud de France brand in the region Languedoc-Roussillon, which is mainly used for the valorisation and promotion of local wines, food and tourism, but also serving institutional aims. It is a study of local dynamics and the process of regional branding, leading to beneficial outcomes stemming from a public development intervention. It demonstrates various economic and non-economic benefits created by a place brand and unfolds some of its working mechanisms, such as horizontal and vertical relations among different territorial actors, a multiple stakeholder involvement, or the linkage of a place brand with its political, social and economic context.

Chapter 3 is a continuation of Chapter 2, as it further investigates the kind of value that can be created by a place brand for different stakeholders, using the Sud de France case. Based on stakeholder and brand equity theory, it develops a measurement model and monitoring tool for the value of place brands. Results show that various place brand value dimensions coexist, according to the expectations of four identified key stakeholder groups. These value dimensions include economic, socio-cultural and environmental indicators.

Chapter 4 offers a comparison of four regional branding initiatives in Europe, with the aim to gain insights into the general conditions, as well as context-dependent factors for successfully developing and maintaining place brands. It combines a marketing perspective with the sociology of food and endogenous rural development, and analyses strategic and operational brand management aspects, as well as contextual factors. Findings indicate the importance of various embeddedness dimensions for regional branding, such as public policies, cooperation and governance forms, territorial identity and the anchorage of local actors in their places.

Chapter 5 is an explorative case study of place branding in the province of Chefchaouen, Morocco, in order to find out whether and how it would be possible to implement there a place brand as a coherent and collective territorial development project. Preconditions and various initiatives towards place branding are analysed at three action levels (macro, meso, micro). Specific attention is given to local cooperation and network activities, to leadership and political unity, being strongly related to the question of territorial governance. The main insight gained from the Chefchaouen case is that a collective place brand could be a useful tool for cross-sector cooperation, territorial governance and development, but that currently Moroccan regions still lack sufficient autonomy to fully develop their own territorial projects.

The final chapter builds upon the research findings to highlight conceptual differences between diverse brands related to places. The main conclusion of this thesis is that place brands in regions – in order to be able to support agribusiness and local development – must be considered as more than mere marketing instruments, but as dynamic, collective and embedded territorial development processes. These insights lead to conceptual and theoretical, methodological, as well as policy and managerial implications, for place branding research and practice. A main suggestion for further research is to use complex systems theory to cover the complexity of place brands.

Biorefinery of leafy biomass using green tea residue as a model material
Zhang, C. - \ 2016
Wageningen University. Promotor(en): Johan Sanders, co-promotor(en): Marieke Bruins. - Wageningen : Wageningen University - ISBN 9789462576902 - 156
biorefinery - biomass conversion - leaves - biomass - green tea - tea - alkaline pulping - pectins - lignocellulose - environmental impact - processes - plant protein - food - biobased economy - bioraffinage - biomassaconversie - bladeren - biomassa - groene thee - thee - alkalische pulpbereiding - pectinen - lignocellulose - milieueffect - processen - plantaardig eiwit - voedsel - biobased economy

Summary

With the rapidly growing world population and improving living standards, food demand is increased with a simultaneous desire for less human impact on the environment, such that “Twice the food production at half the ecological footprint” could be the EU goal for 2050. In fact, a boost in food demand is mainly required in developing countries, where the farmlands are limited and/or they are of poor quality. Rather than improving crop-production yield, developing biorefinery technology with unused biomass, such as leaves, in developing countries may be the key to fulfil the food demand.

Four major components, protein, pectin, lignin, and (hemi-) cellulose, account for more than 70% of the materials in leaves in almost all species. Among these components, protein and pectin can be used in food and animal feed, and they are key components for supplementing food production. However, the production and application of leaf products is limited for four reasons: unstable raw materials, complex components, rigid plant cell walls, and underdeveloped leaf logistics and economics. The limitations cause low pectin and protein yields, and low cost-efficiency in current extraction technologies, including mechanical milling, chemical extraction (acid and alkaline), solvent extraction, and ammonia protein extraction. Development of an integrated process for multiple products might be a good option for leaf biorefinery, but the compatibilities of these processes were unknown.

The aim of this study was to develop new processes and applications that optimally utilize all components, particularly protein, of leafy biomass in the feed and/or food industry using green tea residues as a starting material. The method should also be applicable to other leafy biomass. The research started from the development of alkaline protein extraction technology as presented in Chapter 2. We found that in alkaline protein extraction, temperature, NaOH amount, and extraction time are the parameters determining protein yield, while pH and volume of extraction liquid are critical parameters for production cost. After optimization, more than 90% of leaf protein could be extracted at a cost of 102€/ton protein by single step alkaline extraction. The extracted protein nutritional value was comparable to soybean meal and this technique can be adapted to various leafy biomass. Main drawback of this technique is the overuse of alkali, generation of salts, and the destruction of key amino acids, such as lysine, during the extraction. We tried to overcome its drawbacks by developing integrated process with a recycle for chemicals.

Chapter 3, 4, 5, and 6 refer to the integrated biorefinery. For a better design, we investigated how the alkali aided protein extraction (Chapter 3), and proved that alkaline protein extraction was not facilitated by increased solubility or hydrolysis of protein, but positively correlated to leaf tissue disruption. HG pectin, RGII pectin, polyphenols, and organic acids can be extracted before protein. Protein extraction can then be followed by the extraction of cellulose and hemi-cellulose. RGI pectin and lignin yield were both linearly correlated to protein yield, which indicated that they are likely to be the key limitation to leaf protein extraction. Based on the above findings, an integrated biorefinery that combined protein extraction with a pre-treatment was proposed. In Chapter 4, ethanol, viscozyme, and H2O2 were selected for pre-treatments targeting on the removal of polyphenols and pigments, carbohydrates, and lignin accordingly. Ethanol and viscozyme could extract their targeting components efficiently while H2O2 could bleach GTR with no lignin extracted. The best pre-treatment was the combination of viscozyme and 50% ethanol extraction, which not only reduced the use of alkali by 50%, but also improved protein content and its nutritional value. As pectin can be applied for food or chemicals, enzyme and PBS buffer were investigated for pectin extraction (Chapter 5). Both enzyme and PBS buffer extraction could not only extract high yield HG pectin (predominated by galacturonic acid) with no protein extraction, but also reduced alkali usage in subsequent protein extraction. Pectin obtained using PBS buffer could be present in its native form, which can be precipitated by 40% ethanol. Buffer is suggested to extract pectins when pectins are to be used in food. Otherwise, hydrolyzed pectin that mainly contains galacturonic acid, can be converted to other useful chemicals. For this the enzymatic methods, such as using Viscozyme® L, are recommended.

Alkali usage was further optimized. It was found that by using potassium hydroxide, the protein extraction efficiency was similar to that using sodium hydroxide. The waste water, mainly containing potassium salts, can then be used as fertilizer. This technique is highly depending on the location of factories, which should be built close to the field. Alternatively, calcium hydroxide can be used. As calcium salts can be precipitated by CO2 and calcium hydroxide can be regenerated through burning of the precipitate, this scheme is sustainable and adaptable to most situations. However, as calcium also precipitated pectin, ployphenols, and even proteins, the protein yield is relatively low. Although a pre-treatment can improve extraction efficiency of calcium hydroxide, economic results suggested that a pre-treatment is not necessary unless the products obtained by pre-treatment have an attractive market value.

In Chapter 7, we extend our knowledge on leaf biorefinery with some additional experiments and literature. Simplified models of leaf tissues and cell walls were proposed and used to explain the mechanism of alkaline protein extraction. The models were also used to explain other mechanisms for protein extraction; mechanical milling, steam explosion, acid, and enzyme aided extraction. The possible improvements of leaf biorefinery economics were illustrated either by reducing production cost, by e.g. using counter current extraction or ultrafiltration, or by upgrading product value by applying protein and pectin in food. The processes recommended in this thesis show an excellent prospective, in which they are applicable to other leaf biomass and suitable for small-scale production.

Intestinal nutrient sensing : a gut feeling for food
Wielen, N. van der - \ 2016
Wageningen University. Promotor(en): Renger Witkamp, co-promotor(en): Jocelijn Meijerink; Henk F.J. Hendriks. - Wageningen : Wageningen University - ISBN 9789462576995 - 200
obesity - hormones - intestines - gastrointestinal hormones - pancreozymin - vasoactive intestinal peptide - sensing - in vivo experimentation - animal models - in vitro - gastric bypass - food - weight reduction - stevia rebaudiana - release - obesitas - hormonen - darmen - maagdarmhormonen - pancreozymine - vasoactief intestinaal peptide - aftasten - in vivo experimenten - diermodellen - in vitro - buik bypass - voedsel - gewichtsvermindering - stevia rebaudiana - vrijgeven

The alarming increase in obesity rates creates an urgent need for effective prevention and treatment strategies. The most effective treatment for obesity today is bariatric surgery. Bariatric surgery comprises a number of different procedures having in common that they induce weight loss and alter gut hormone release. Gut hormones are well known for their effects on food intake behavior and their role in weight loss after bariatric surgery is undeniable. In addition, the therapeutic use of GLP-1 (Glucagon-Like Peptide-1) analogues including liraglutide in type II diabetes and obesity is on the rise. This underlines why gut hormones are considered promising targets for the development of new treatment strategies against obesity and its comorbidities.

The secretion of gut hormones, among which GLP-1, is influenced by nutrient ingestion. The interactions of dietary components or their breakdown products with receptors and transporters located on the enteroendocrine cells of the intestinal tract can induce their release, a process called intestinal nutrient sensing. In this thesis, we aimed to further elucidate intestinal nutrient sensing mechanisms on a cellular level. First, the regional expression of several gut nutrient sensing related genes along the intestinal tract was assessed in three commonly studied species, namely mouse, pig and man. Gene expression of receptors, transporters and peptides involved in nutrient sensing shows a distinctive distribution pattern along the small intestine, which is in the distal small intestine highly similar between the species. Subsequently, we sought to investigate if this expression was changed after a weight loss inducing bariatric procedure. By whole transcriptome analysis, we showed that upper gastrointestinal tissue expression of genes associated with nutrient sensing was hardly changed. In contrast, a considerable reduction in inflammatory pathways was observed.

Next, we sought to investigate the effects of the non-caloric sweetener rebaudioside A. This Stevia rebaudiana-derived compound was approved on the European market in 2011. As there is still some controversy about the effects of sweeteners in general on GLP-1 release, we investigated the effects of this specific sweetener. Because of the short half-life of GLP-1, the effect of nutrient stimulation was mainly studied in ex vivo and in vitro models in which local intestinal hormone release could be determined. A two dimensional gut model using intestinal organoids derived from murine intestinal crypts was developed to study location-specific hormone secretion. Rebaudioside A was found to induce GLP-1 and PYY release ex vivo from porcine intestinal tissue and in two dimensional organoids. This induction of the release was specific for the intestinal location, with the ileum being most potently stimulated by rebaudioside A. Moreover, prolonged exposure to rebaudioside A increased enteroendocrine cell numbers in two dimensional organoids. When studying the underlying mechanism in enteroendocrine STC-1 cells, we concluded that rebaudioside A-induced GLP-1 release was independent of the sweet taste receptor.

The studies presented in this thesis add to our understanding the role of receptors and other molecular structures that are likely to be involved in nutrient sensing and the modulation of gut hormone release. What we know now is that several factors play a role in gut hormone release. This includes not only the nature and dose of the active compound(s), but also the location and timing of its (their) interactions with receptors and other targets along the gastrointestinal tract. We have shown that rebaudioside A may be a potential compound to induce gut hormone release in vivo, especially when applied to the distal small intestine. Therefore, rebaudioside A may be a promising compound to influence food intake, possibly most potent when delivered in the ileum.

Gedragscode eerlijke handelspraktijken : quick-scanevaluatie
Heide, C.M. van der; Wagenberg, C.P.A. van; Judge, L.O. - \ 2016
Wageningen : LEI Wageningen UR (LEI report 2016-022) - ISBN 9789462577299 - 27 p.
agro-industriële sector - landbouwindustrie - voedsel - mode - textiel - schoeisel - fair trade - gedragscode - agroindustrial sector - agribusiness - food - fashion - textiles - footwear - code of practice
The agrofood sector, and the fashion, textiles and footwear sector have been working towards the drafting and implementation of a code of conduct with possibilities for dispute resolution in order to promote fair trade practices. Steering groups from within each of these two sectors started a pilot in order to achieve this. For the 2 years that these pilots were running, the two steering groups did not receive any complaints about unfair trade practices. Both steering groups emphasised that they determined that a code of conduct does have an edifying effect. The general perception is that the code of conduct made businesses more aware of fair trade and unfair trade practices. The steering group from the agrofood sector, although not unanimously, is sympathetic towards a continuation of the pilot which is in contrast with the steering group from the fashion, textile and footwear sector. This steering group supports putting the current pilot on hold and to make it available on demand if the branch organisations advise its usage. Both steering groups do not support extra legislation in this area.
Lubrication and perception of foods : tribological, rheological and sensory properties of particle-filled food system
Liu, K. - \ 2016
Wageningen University. Promotor(en): Erik van der Linden, co-promotor(en): Markus Stieger; Fred van de Velde. - Wageningen : Wageningen University - ISBN 9789462576803 - 236
rheological properties - tribology - fat globules - particles - lubrication - sensory evaluation - simulation models - food - gels - rice - reologische eigenschappen - tribologie - vetbolletjes - deeltjes - smering - sensorische evaluatie - simulatiemodellen - voedsel - gels - rijst

Background and aims

Food structure is determined by its composition and the interaction between the compositional or structural elements. Both food structure and the texture perception of foods undergo dynamic changes during different phases of oral processing. During oral processing, both rheological and tribological properties of foods are relevant for sensory perception. The general aim of this thesis was to understand the relationship between the structural properties, rheological and tribological properties during food breakdown, and the sensory perception of foods. More specifically, this thesis aimed to link the properties of food particles in liquid and semi-solid matrices to the tribological and rheological properties, and in this way, understand the sensory perception of these systems.

Methods

Fat droplets and micro-particle fat replacers based on protein and starch were investigated. These particles varied in size, morphology, deformability and stability, as well as their interaction with the surrounding matrix. These particles were dispersed in liquid or semi-solid gel phases, forming the food model systems under consideration. The friction and microstructural evolution of food model systems under shear was determined using a mouth-mimicking tribometer connected to a confocal laser scanning microscopy. The viscosities of liquid systems were analyzed using a rheometer, and the large deformation properties of semi-solid gel systems were determined during uniaxial compression tests. The sensory perception of the food model systems were measured using quantitative descriptive analysis. The release and deposition of fat droplets on the tongue were determined using in vivo fluorescence.

Results

Food structural elements could be manipulated to control the tribological properties of food model systems. Morphology, size, and deformability of food particles determine the lubrication behavior of the food systems. Spherical particles with micrometer size were able to reduce friction through a ball bearing mechanism, while irregularly shaped particles increased friction by increasing apparent surface asperity contacts. Deformable particles could flatten the surface by filling asperities, thus reduced friction. Coalescence of unstable droplets could plate-out on the surface and form film patches, thus reduced friction. Other structural elements, such as emulsifiers and sticky molecules, also influenced tribological properties of the systems. Interactions between the food structural elements could influence the rheological properties of liquid and semi-solid food systems. These properties as well as tribological properties were inter-related and all of them affect sensory perception. The inter-relations between physical and sensory properties of food systems were influenced by oral processing, such as oral processing duration and temperature. Furthermore, several fat reduction and replacement strategies were suggested, including increasing the availability of fat that is in contact with oral surfaces, improving the lubrication by ball bearing of particles, and reducing perception of negative attributes such as roughness.

Conclusions

This thesis showed the importance of food particle properties in both the tribological properties and sensory perception of foods, and emphasized the different lubrication mechanisms of different structure elements and their relation to perception. The differences in behavior of food particles between liquid and semi-solid gel systems were highlighted. These findings would enable a better understanding of relationship between food structure and their physical and sensory properties, and this would allow designing or modifying food products with targeted texture and sensory perception.

Electrostatic separation for functional food ingredient production
Wang, J. - \ 2016
Wageningen University. Promotor(en): Maarten Schutyser, co-promotor(en): Remko Boom. - Wageningen : Wageningen University - ISBN 9789462576513 - 176
particles - fractionation - separation - electrostatic separation - sieving - nitrogen - polystyrenes - wheat gluten - arabinoxylans - starch - milling - lupinus - rice bran - food - experiments - deeltjes - fractionering - scheiding - elektrostatische scheiding - zeven (activiteit) - stikstof - polystyrenen - tarwegluten - arabinoxylanen - zetmeel - maling - lupinus - rijstzemelen - voedsel - experimenten

Summary

Dry fractionation is a promising alternative to wet extraction processes for production of food ingredients, since it uses hardly any water, consumes less energy and retains the native functionality of the ingredients. It combines milling and dry separation to enrich agro-materials in specific components such as protein. Electrostatic separation recently emerged as a novel dry separation process and it relies on electrostatic forces for separation. Though the potential of electrostatic separation to fractionate agro-materials has been demonstrated, the effectiveness in terms of purity and yield and the influence of process parameters on charging and separation of food ingredients have not yet been systematically studied. Therefore, the objective of this thesis was to gain better understanding of the charging and separation behaviour of model and agro-materials, provide insight in the critical factors for successful electrostatic separation and explore the potential of this separation method to different agro-materials.

The charging step is critical to the effectiveness of electrostatic separation and is influenced by many factors. Chapter 2 presents characterization of the charging behaviour of single-component model particles in nitrogen gas flowing through aluminium tubes, using a lab-scale electrostatic separator. Polystyrene particles and wheat gluten were used as model particles. Higher gas velocities led to a higher specific charge by increasing the normal component of impact velocity. Smaller particles gained more specific charge than larger ones because of their higher surface to volume ratio and their sensitivity towards gas flow pattern changes. Longer charging tube lengths allowed more contact between the particles and the wall and therefore resulted in higher specific charge. The relative humidity of the nitrogen gas flow within the range 0 – 60% had no influence on the charging behaviour of both model particles.

Chapter 3 demonstrates the potential of applying electrostatic separation to enrich arabinoxylans from wheat bran with the same lab-scale electrostatic separator. A combination of larger particle size, higher gas velocity and shorter charging tube was preferred for separation, because it sufficiently charged the particles while agglomeration was minimized. Electrostatic separation with the optimum setting achieved a similar enrichment in arabinoxylans (from 23% to 30% dry matter basis) as sieving does. However, the combination of electrostatic separation and sieving further improved the enrichment and resulted in a fraction with an arabinoxylans content of 43% dry matter basis, which is around the maximum achievable purity that can be reached by dry fractionation.

To allow better defined charging and separation experiments, a bench-scale electrostatic separator was designed and constructed. With this custom-built separator, the charging and separation of model mixtures prepared from wheat gluten and starch were studied in chapter 4. The net charge of gluten-starch mixtures was not simply the sum of the charge of the two individual components, indicating that particle-particle interactions play an important role. We hypothesized that the formation of agglomerates between oppositely charged particles negatively influenced separation, which was supported by the fact that the dispersibility for mixtures of the two components was lower compared to that of individual components. We found that during electrostatic separation of mixtures, it is important to find the optimal condition that provides sufficient charge to charges, but avoids agglomeration between oppositely charged particles. This could be achieved by the combination of lower dosing rate and higher gas flow rate.

Chapter 5 reports on dry fractionation by combining milling and electrostatic separation with the custom-built bench-scale separator, providing an alternative to wet extraction of protein from lupine seeds. Relatively coarse milling was preferred because it disclosed sufficient protein bodies from the matrix, while avoiding poor dispersibility of the powder due to its very fine particle size. With the optimal settings of single-step electrostatic separation, a fraction with 57.3 g/100 g dry solids could be obtained. The protein content was further improved to 65.0% dry matter basis after two more separation steps, which is 15% higher than obtained by air classification. The yield of the protein enriched fraction was further increased by recycling the fractions from the filter bags, but this was accompanied by a decrease in protein content and vice versa. A significant shift towards better yield and purities was achieved by re-milling the flour that was not collected on the electrodes. A final fraction with a protein content of 65.1% dry matter basis and a yield of 6% was obtained, which recovered 10% of the protein in the original flour.

Chapter 6 explores the possibility of enriching dietary fibre from defatted rice bran by dry fractionation, where the custom-built bench-scale electrostatic separator was used. All three tested separation routes produced fibre-enriched fractions with similar yield (20 – 21 % of the milled flour) and fibre content (67 – 68 % dry matter basis), which recovered 42 – 48 % of the fibre from the original flour. The enriched fractions obtained by a two-step electrostatic separation process contained more small particles compared to the other two, which resulted in different functional properties. Compared to the total dietary fibre extracted by the enzymatic-gravimetric method, the enriched fractions by dry fractionation had a similar water retention capacity and oil binding capacity. This suggests that the fibre-enriched fractions by dry fractionation can be applied in foods and provide similar technological properties and physiological effects as the wet-extracted dietary fibre does.

Chapter 7 concludes the thesis with a general discussion on the main findings, based on which two schemes for protein enrichment and fibre enrichment were proposed. Subsequently the challenges to achieve a successful electrostatic separation for agro-material and up-scaling are discussed. Finally, the chapter ends with an outlook on future research.

This thesis provided insight in the key factors for successful electrostatic separation. It demonstrated the potential of applying this separation method for functional ingredient production from different agro-materials and also gave directions for further improvement and scaling-up.

Beyond liking : emotional and physiological responses to food stimuli
He, W. - \ 2016
Wageningen University. Promotor(en): Kees de Graaf, co-promotor(en): Sanne Boesveldt; Rene de Wijk. - Wageningen : Wageningen University - ISBN 9789462576506 - 149
stimuli - food - emotions - autonomic nervous system - odours - taste - beverages - physiological functions - man - human behaviour - expressivity - prikkels - voedsel - emoties - autonome zenuwstelsel - geurstoffen - smaak - dranken - fysiologische functies - mens - menselijk gedrag - expressiviteit

Background and aim

Traditional liking ratings are typically seen as an important determinant in eating behavior. However, in order to better understand eating behavior, we need to first better understand (the dynamic and implicit features underlying) liking appraisal. The aim of this thesis was to investigate the effects of food stimuli varying in sensory modality (smell and taste), pleasantness and intensity, on emotional and physiological responses leading up to liking appraisal.

Methods

Four studies, using healthy participants, were conducted as part of this thesis. In the first study, responses to pleasant versus unpleasant food odors varying in intensity were measured discretely using pleasantness ratings, intensity ratings and non-verbally reported emotions (PrEmo), as well as continuously using facial expressions and autonomic nervous system (ANS) responses. To further explore how explicit and implicit factors contribute to pleasantness appraisal, the same measures were assessed in response to food odors with a wider range of valence. Next, we focused on facial expressions and ANS responses elicited by single sips of breakfast drinks that were equally liked. In the last study, we investigated changes in pleasantness after consuming semi-liquid meals to (sensory-specific) satiety, combined with measures of facial expressions and ANS responses.

Results

Both non-verbal reported emotions and emotional facial expressions were demonstrated to be able to discriminate between food odors differing in pleasantness and between food odors differing in intensity. In addition to discrete emotional responses, odor valence associated best with facial expressions after 1 second of odor exposure. Furthermore, facial expressions and ANS responses measured continuously were found odor-specific in different rates over time. Results of food odors with a wider range of valence showed that non-verbally reported emotions, facial expressions and ANS responses correlated with each other best in different time windows after odor presentation: facial expressions and ANS responses correlated best with the explicit emotions of the arousal dimension in the 2nd second of odor presentation, whereas later ANS responses correlated best with the explicit emotions of the valence dimension in the 4th second. For food stimuli varying in flavor (breakfast drinks), facial expressions and ANS responses showed strongest associations with liking after 1 second of tasting, as well as with intensity after 2 seconds of tasting. Lastly, we were able to demonstrate that ANS responses, as well as facial expressions of anger and disgust were associated with satiety. Further effects of sensory-specific satiety were also reflected by skin conductance, skin temperature, as well as facial expressions of sadness and anger.

Conclusions

Both non-verbal reported emotions and emotional facial expressions were demonstrated to be able to discriminate between food odors differing in pleasantness and/or intensity. Explicit and implicit emotional responses, as well as physiological patterns are related to liking appraisals involved in smelling foods. Implicit measures such as facial expressions and ANS responses can provide more multidimensional information for both food odors and tastes than explicit measures and prove to be highly dynamic over time with specific time courses. Early implicit facial and ANS responses primarily reflect emotion arousal, whereas later ANS responses reflect emotion valence, suggesting dynamic unfolding of different appraisals of food stimuli. Furthermore, ANS responses and facial expressions can reflect pleasantness, satiety, and a combination of both: sensory-specific satiety. This suggests that implicit processes play an important role in dynamic liking appraisals with respect to eating behavior.

Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.